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lt3467/lt3467a 1 3467afe typical application description 1.1a step-up dc/dc converter with integrated soft-start the lt ? 3467/lt3467a switching regulators combine a 42v, 1.1a switch with a soft-start function. pin compatible with the lt1930, its low v cesat bipolar switch enables the device to deliver high current outputs in a small footprint. the lt3467 switches at 1.3mhz, allowing the use of tiny, low cost and low height inductors and capacitors. the lt3467a switches at 2.1mhz, allowing the use of even smaller components. high inrush current at start-up is eliminated using the programmable soft-start function. a single external capacitor sets the current ramp rate. a constant frequency current mode pwm architecture results in low, predictable output noise that is easy to ? lter. the high voltage switch on the lt3467/lt3467a is rated at 42v, making the devices ideal for boost converters up to 40v as well as sepic and ? yback designs. the lt3467 can generate 5v at up to 540ma from a 3.3v supply or 5v at 450ma from four alkaline cells in a sepic design. the lt3467a can generate 5v at up to 430ma from a 3.3v supply or 15v at 135ma from a 3.3v supply. the lt3467/ lt3467a are available in a low pro? le (1mm) 6-lead sot-23 package and tiny 3mm 2mm dfn package. l , lt, ltc, ltm, linear technology and the linear logo are registered trademarks of linear technology corporation. thinsot is a trademark of linear technology corporation. all other trademarks are the property of their respective owners. single li-ion cell to 5v boost converter features applications n 1.3mhz switching frequency (lt3467) n 2.1mhz switching frequency (lt3467a) n low v cesat switch: 330mv at 1.1a n high output voltage: up to 40v n wide input range: 2.4v to 16v n dedicated soft-start pin n 5v at 540ma from 3.3v input (lt3467) n 5v at 430ma from 3.3v input (lt3467a) n 12v at 270ma from 5v input (lt3467) n 12v at 260ma from 5v input (lt3467a) n uses small surface mount components n low shutdown current: <1a n pin-for-pin compatible with the lt1930 and lt1613 n low pro? le (1mm) thinsot ? package n low pro? le (0.75mm) 8-lead (3mm 2mm) dfn package n digital cameras n white led power supplies n cellular phones n medical diagnostic equipment n local 5v or 12v supplies n tft-lcd bias supplies n xdsl power supplies gnd v in sw ss fb v in 2.6v to 4.2v 2.7h 402k lt3467 3467 ta01a 15f 3.3pf 4.7f 133k v out 5v 765ma at v in = 4.2v, 540ma at v in = 3.3v, 360ma at v in = 2.6v shdn off on 0.047f i out (ma) efficiency (%) 600 95 90 85 80 75 70 65 60 55 50 3467 ta01b 100 900 200 300 400 500 700 800 v in = 3.3v v in = 4.2v v in = 2.6v ef? ciency
lt3467/lt3467a 2 3467afe v in voltage ................................................................16v sw voltage ................................................ C0.4v to 42v fb voltage ................................................................2.5v current into fb pin .............................................. 1ma shdn voltage ......................................................... 16v maximum junction temperature ......................... 125c (note 1) order information absolute maximum ratings top view 9 ddb package 8-lead (3mm s 2mm) plastic dfn 5 6 7 8 4 3 2 1 fb gnd sw sw shdn ss v in gnd t jmax = 125c, ja = 80c/w exposed pad (pin 9) is gnd, must be soldered to pcb 6 v in 5 ss 4 shdn sw 1 top view s6 package 6-lead plastic tsot-23 gnd 2 fb 3 t jmax = 125c, ja = 165c/w, jc = 102c/w pin configuration operating junction temperature range (note 2) e grade ................................................ C40c to 85c i grade ............................................... C40c to 125c storage temperature range ................... C65c to 150c lead temperature (soldering, 10 sec) tsot ................................................................. 300c lead free finish tape and reel part marking* package description temperature range lt3467eddb#pbf lt3467eddb#trpbf lcpx 8-lead (3mm 2mm) plastic dfn C40c to 85c lt3467iddb#pbf lt3467iddb#trpbf lcpx 8-lead (3mm 2mm) plastic dfn C40c to 125c lt3467aeddb#pbf lt3467aeddb#trpbf lckd 8-lead (3mm 2mm) plastic dfn C40c to 85c lt3467aiddb#pbf lt3467aiddb#trpbf lckd 8-lead (3mm 2mm) plastic dfn C40c to 125c lt3467is6#pbf lt3467is6#trpbf ltach 6-lead plastic tsot-23 C40c to 125c lt3467es6#pbf lt3467es6#trpbf ltach 6-lead plastic tsot-23 C40c to 85c lt3467aes6#pbf lt3467aes6#trpbf ltbcc 6-lead plastic tsot-23 C40c to 85c lt3467ais6#pbf lt3467ais6#trpbf ltbcc 6-lead plastic tsot-23 C40c to 125c lead based finish tape and reel part marking* package description temperature range lt3467eddb lt3467eddb#tr lcpx 8-lead (3mm 2mm) plastic dfn C40c to 85c lt3467iddb lt3467iddb#tr lcpx 8-lead (3mm 2mm) plastic dfn C40c to 125c lt3467aeddb lt3467aeddb#tr lckd 8-lead (3mm 2mm) plastic dfn C40c to 85c lt3467aiddb lt3467aiddb#tr lckd 8-lead (3mm 2mm) plastic dfn C40c to 125c lt3467is6 lt3467is6#tr ltach 6-lead plastic tsot-23 C40c to 125c lt3467es6 lt3467es6#tr ltach 6-lead plastic tsot-23 C40c to 85c lt3467aes67 lt3467aes6#tr ltbcc 6-lead plastic tsot-23 C40c to 85c lt3467ais67 lt3467ais67#tr ltbcc 6-lead plastic tsot-23 C40c to 125c consult ltc marketing for parts speci? ed with wider operating temperature ranges. *the temperature grade is identi? ed by a label on the shipping container. for more information on lead free part marking, go to: http://www.linear.com/leadfree/ for more information on tape and reel speci? cations, go to: http://www.linear.com/tapeandreel/
lt3467/lt3467a 3 3467afe electrical characteristics note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: the lt3467e/lt3467ae are guaranteed to meet performance speci? cations from 0c to 85c, junction temperature. speci? cations over the C40c to 85c operating junction temperature range are assured by design, characterization and correlation with statistical process controls. the lt3467i/lt3467ai are guaranteed over the full C40c to 125c operating junction temperature range. the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. v in = 3v, v shdn = v in unless otherwise noted. speci? cations are for both the lt3467 and lt3467a unless otherwise noted. parameter conditions min typ max units minimum operating voltage 2.2 2.4 v maximum operating voltage 16 v feedback voltage l 1.230 1.220 1.255 1.270 1.280 v v fb pin bias current (note 3) l 10 50 na quiescent current v shdn = 2.4v, not switching 1.2 2 ma quiescent current in shutdown v shdn = 0.5v, v in = 3v 0.01 1 a reference line regulation 2.6v v in 16v 0.01 0.05 %/v switching frequency lt3467 lt3467a lt3467a l 1 1.6 1.6 1.3 2.1 1.6 2.7 mhz mhz mhz maximum duty cycle lt3467 lt3467 lt3467a lt3467a l l 88 87 82 78 94 88 % % % % minimum duty cycle 10 % switch current limit at minimum duty cycle at maximum duty cycle (note 4) 1.4 0.8 1.8 1.2 2.5 1.9 a a switch v cesat i sw = 1.1a 330 500 mv switch leakage current v sw = 5v 0.01 1 a shdn input voltage high 2.4 v shdn input voltage low 0.5 v shdn pin bias current v shdn = 3v v shdn = 0v 16 0 32 0.1 a a ss charging current v ss = 0.5v 2 3 4.5 a note 3: current ? ows out of the pin. note 4: see typical performance characteristics for guaranteed current limit vs duty cycle.
lt3467/lt3467a 4 3467afe typical performance characteristics current limit vs duty cycle switch saturation voltage vs switch current oscillator frequency vs temperature soft-start current vs soft-start voltage peak switch current vs soft-start voltage start-up waveform (figure 2 circuit) quiescent current vs temperature fb pin voltage vs temperature shdn current vs shdn voltage i q (ma) temperature (c) C40 95 110 3467 g01 5 C10 50 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 C25 35 20 65 80 125 v fb (v) temperature (c) C40 95 110 3467 g02 5 C10 50 1.26 1.25 1.24 1.23 1.22 1.21 1.20 C25 35 20 65 80 125 v shdn (v) 0 i shdn (a) 8 140 120 100 80 60 40 20 0 3467 g03 416 12 2 10 618 14 t a = 25c dc (%) 10 i lim (a) 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 30 50 60 3467 g04 20 40 70 80 90 typical guaranteed t a = 25c v cesat 100mv/div sw current 200ma/div t a = 85c t a = 25c t a = C40c 3467 g05 temperature (c) C50 oscillator frequency (mhz) 100 3467 g06 050 C25 25 75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 0 lt3467a lt3467 v ss (mv) 0 50 150 250 350 450 i ss (a) 6 5 4 3 2 1 0 100 200 300 400 3467 g07 500 t a = 25c v ss (mv) 0 50 150 250 350 450 switch current (a) 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 100 200 300 400 3467 g08 500 t a = 25c v shdn 2v/div v out 1v/div i supply 0.5a/div 0.5ms/div 3467 g09
lt3467/lt3467a 5 3467afe pin functions (dfn/tsot) fb (pin 1/pin 3): feedback pin. reference voltage is 1.255v. connect resistive divider tap here. minimize trace area at fb. set v out = 1.255v(1 + r1/r2). gnd (pins 2, 5, 9/pin 2): ground. tie directly to local ground plane. sw (pins 3, 4/pin 1): switch pin. (collector of internal npn power switch) connect inductor/diode here and minimize the metal trace area connected to this pin to minimize emi. v in (pin 6/pin 6): input supply pin. must be locally bypassed. ss (pin 7/pin 5): soft-start pin. place a soft-start capacitor here. upon start-up, 4a of current charges the capacitor to 1.255v. use a larger capacitor for slower start-up. leave ? oating if not in use. shdn (pin 8/pin 4): shutdown pin. tie to 2.4v or more to enable device. ground to shut down. block diagram C + C + rq s 0.01 sw driver comparator shdn v in ss fb C + 3 ramp generator 1.255v reference r c c c 1.3mhz oscillator* gnd 3467 f01 q1 a2 a1 r1 (external) r2 (external) fb v out shutdown 250k *2.1mhz for lt3467a figure 1. block diagram
lt3467/lt3467a 6 3467afe applications information operation the lt3467 uses a constant frequency, current-mode con- trol scheme to provide excellent line and load regulation. refer to the block diagram. at the start of each oscillator cycle, the sr latch is set which turns on the power switch q1. a voltage proportional to the switch current is added to a stabilizing ramp and the resulting sum is fed into the positive terminal of the pwm comparator a2. when this voltage exceeds the level at the negative input of a2, the sr latch is reset, turning off the power switch. the level at the negative input of a2 is set by the error ampli? er a1, and is simply an ampli? ed version of the difference between the feedback voltage and the reference voltage of 1.255v. in this manner, the error ampli? er sets the correct peak current level to keep the output in regulation. if the error ampli? ers output increases, more current is delivered to the output. similarly, if the error decreases, less current is delivered. the soft-start feature of the lt3467 allows for clean start-up conditions by limiting the rate of voltage rise at the output of comparator a1 which, in turn, limits the peak switch current. the soft-start pin is connected to a reference voltage of 1.255v through a 250k resistor, providing 4a of current to charge the soft-start capacitor. typical values for the soft-start capacitor range from 10nf to 200nf. the lt3467 has a current limit circuit not shown in the block diagram. the switch current is constantly monitored and not allowed to exceed the maximum switch current (typically 1.4a). if the switch current reaches this value, the sr latch is reset regardless of the state of comparator a2. this current limit protects the power switch as well as the external components connected to the lt3467. the block diagram for the lt3467a (not shown) is identical except that the oscillator frequency is 2.1mhz. duty cycle the typical maximum duty cycle of the lt3467 is 94% (88% for the lt3467a). the duty cycle for a given ap- plication is given by: dc = |v out | + |v d |?|v in | |v out | + |v d |?|v cesat | where v d is the diode forward voltage drop and v cesat is in the worst case 330mv (at 1.1a) the lt3467 and lt3467a can be used at higher duty cycles, but must be operated in the discontinuous conduction mode so that the actual duty cycle is reduced. setting output voltage r1 and r2 determine the output voltage. v out = 1.255v (1+ r1/r2) switching frequency and inductor selection the lt3467 switches at 1.3 mhz, allowing for small valued inductors to be used. 4.7h or 10h will usually suf? ce. the lt3467a switches at 2.1mhz, allowing for even smaller valued inductors to be used. 0.9h to 6.8h will usually suf? ce. choose an inductor that can handle at least 1.2a without saturating, and ensure that the inductor has a low dcr (copper-wire resistance) to minimize i 2 r power losses. note that in some applications, the current handling requirements of the inductor can be lower, such as in the sepic topology where each inductor only carries one-half of the total switch current. for better ef? ciency, use similar valued inductors with a larger volume. many different sizes and shapes are available from various manufacturers. choose a core material that has low losses at 1.3mhz, (2.1mhz for the lt3467a) such as ferrite core.
lt3467/lt3467a 7 3467afe applications information gnd v in sw ss fb v in 2.6v to 4.2v d1 l1 2.7h r1 402k lt3467 3467 ta05a c2 15f c4 3.3pf c1 4.7f r2 133k v out 5v 765ma at v in = 4.2v, 540ma at v in = 3.3v, 360ma at v in = 2.6v c1, c2: x5r or x7r, 6.3v d1: on semiconductor mbrm120 l1: sumida cr43-2r7 shdn off on c3 0.047f figure 2. single li-ion cell to 5v boost converter (same as 1st page application) table 1. inductor manufacturers sumida (847) 956-0666 www.sumida.com tdk (847) 803-6100 www.tdk.com murata (714) 852-2001 www.murata.com fdk (408) 432-8331 www.fdk.co.jp soft-start the soft-start feature provides a way to limit the inrush current drawn from the supply upon start-up. an internal 250k resistor charges the external soft-start capacitor to 1.255v. after the capacitor reaches 0.15v the rate of voltage rise at the output of the comparator a1 tracks the rate of voltage rise of the soft-start capacitor. this limits the inrush current drawn from the supply during start- up. the soft-start feature plays another important role in applications where the switch will reach levels of 30v or higher. during start-up, excessively high switch current, together with the presence of high voltage can overstress the switch. a properly used soft-start feature will keep the switch current from overshooting. this practice will greatly improve the robustness of such designs. once the part is shut down, the soft-start capacitor is quickly discharged to 0.4v, then slowly discharged through the 250k resistor to ground. if the part is to be shut down and re-enabled in a short period of time while soft-start is used, you must ensure that the soft-start capacitor has enough time to discharge before re-enabling the part. typical values of the soft-start capacitor range from 10nf to 200nf. supply current of figure 2 during start-up without soft-start capacitor v out 1v/div i supply 0.5a/div 0.1ms/div 3467 ai01 supply current of figure 2 during start-up with a 47nf soft-start capacitor v out 1v/div i supply 0.5a/div 0.5ms/div 3467 ai02
lt3467/lt3467a 8 3467afe applications information capacitor selection low esr (equivalent series resistance) capacitors should be used at the output to minimize the output ripple voltage. multi-layer ceramic capacitors are an excellent choice, as they have extremely low esr and are available in very small packages. x5r dielectrics are preferred, followed by x7r, as these materials retain the capacitance over wide voltage and temperature ranges. a 4.7f to 15f output capacitor is suf? cient for most applications, but systems with very low output currents may need only a 1f or 2.2f output capacitor. solid tantalum or os-con capacitors can be used, but they will occupy more board area than a ceramic and will have a higher esr. always use a capacitor with a suf? cient voltage rating. ceramic capacitors also make a good choice for the input decoupling capacitor, which should be placed as close as possible to the lt3467. a 1f to 4.7f input capacitor is suf? cient for most applications. table 2 shows a list of several ceramic capacitor manufacturers. consult the manufacturers for detailed information on their entire selection of ceramic parts. table 2. ceramic capacitor manufacturers taiyo yuden (408) 573-4150 www.t-yuden.com avx (803) 448-9411 www.avxcorp.com murata (714) 852-2001 www.murata.com the decision to use either low esr (ceramic) capacitors or the higher esr (tantalum or os-con) capacitors can affect the stability of the overall system. the esr of any capacitor, along with the capacitance itself, contributes a zero to the system. for the tantalum and os-con ca- pacitors, this zero is located at a lower frequency due to the higher value of the esr, while the zero of a ceramic capacitor is at a much higher frequency and can generally be ignored. a phase lead zero can be intentionally introduced by placing a capacitor (c4) in parallel with the resistor (r1) between v out and v fb as shown in figure 2. the frequency of the zero is determined by the following equation. ? z = 1 2 ?r1?c4 by choosing the appropriate values for the resistor and capacitor, the zero frequency can be designed to improve the phase margin of the overall converter. the typical target value for the zero frequency is between 35khz to 55khz. figure 3 shows the transient response of the step-up converter from figure 8 without the phase lead capacitor c4. although adequate for many applications, phase margin is not ideal as evidenced by 2-3 bumps in both the output voltage and inductor current. a 22pf capacitor for c4 results in ideal phase margin, which is revealed in figure 4 as a more damped response and less overshoot. diode selection a schottky diode is recommended for use with the lt3467 and the lt3467a. the philips pmeg 2005 is a very good choice. where the switch voltage exceeds 20v, use the pmeg 3005 (a 30v diode). where the switch voltage exceeds 30v, use the pmeg 4005 (a 40v diode). these diodes are rated to handle an average forward current of 0.5a. in applications where the average forward current of the diode exceeds 0.5a, a philips pmeg 2010 rated at 1a is recommended. for higher ef? ciency, use a diode with better thermal characteristics such as the on semi- conductor mbrm120 (a 20v diode) or the mbrm140 (a 40v diode).
lt3467/lt3467a 9 3467afe applications information v out 200mv/div ac coupled i l1 5a/div ac coupled load current 100ma/div ac coupled 20s/div 3467 f03 figure 3. transient response of figure 8s step-up converter without phase lead capacitor v out 200mv/div ac coupled i l1 5a/div ac coupled load current 100ma/div ac coupled 20s/div 3467 f04 figure 4. transient response of figure 8s step-up converter with a 22pf phase lead capacitor setting output voltage to set the output voltage, select the values of r1 and r2 (see figure 2) according to the following equation. r1 = r2 v out 1.255v ?1 ? ? ? ? ? ? a good value for r2 is 13.3k which sets the current in the resistor divider chain to 1.255v/13.3k = 94a. layout hints the high speed operation of the lt3467/lt3467a demands careful attention to board layout. you will not get adver- tised performance with careless layout. figure 5a shows the recommended component placement for the thinsot package. figure 5b shows the recommended component placement for the dfn package. note the vias under the exposed pad. these should connect to a local ground plane for better thermal performance. r2 r1 gnd c2 c3 l1 d1 c1 v out v out v in shdn 3467 f05a fb c ss ss 1 2 3 6 5 4 figure 5a. suggested layoutthinsot r2 r1 gnd c2 c1 l1 d1 v out v out 3467 f05b c3 fb c ss v in 1 2 3 4 8 7 6 5 shdn figure 5b. suggested layoutdfn
lt3467/lt3467a 10 3467afe applications information compensationtheory like all other current mode switching regulators, the lt3467/lt3467a needs to be compensated for stable and ef? cient operation. two feedback loops are used in the lt3467/lt3467a: a fast current loop which does not require compensation, and a slower voltage loop which does. standard bode plot analysis can be used to under- stand and adjust the voltage feedback loop. as with any feedback loop, identifying the gain and phase contribution of the various elements in the loop is critical. figure 6 shows the key equivalent elements of a boost converter. because of the fast current control loop, the power stage of the ic, inductor and diode have been re- placed by the equivalent transconductance ampli? er g mp . g mp acts as a current source where the output current is proportional to the v c voltage. note that the maximum output current of gmp is ? nite due to the current limit in the ic. from figure 6, the dc gain, poles and zeroes can be calculated as follows: output pole: p1= 2 2? ?r l ?c out error amp pole: p2= 1 2? ?r o ?c c error amp zero: z1= 1 2? ?r c ?c c dc gain: a= 1.255 v out 2 ?v in ?g ma ?r o ?g mp ?r l ? 1 2 esr zero: z2 = 1 2? ?r esr ?c out rhp zero: z3= v in 2 ?r l 2? ?v out 2 ?l high frequency pole: p3> f s 3 phase lead zero: z4 = 1 2? ?r1?c pl phase lead pole: p4 = 1 2? ?c pl ? r1? r2 r1 + r2 the current mode zero is a right-half plane zero which can be an issue in feedback control design, but is manageable with proper external component selection. C + C + g ma r c r o r2 c c : compensation capacitor c out : output capacitor c pl : phase lead capacitor g ma : transconductance amplifier inside ic g mp : power stage transconductance amplifier r c : compensation resistor r l : output resistance defined as v out divided by i load(max) r o : output resistance of g ma r1, r2: feedback resistor divider network r esr : output capacitor esr 3467 f06 r1 c out c pl r l r esr v out v c c c g mp 1.255v reference figure 6. boost converter equivalent model
lt3467/lt3467a 11 3467afe applications information using the circuit of figure 2 as an example, the following table shows the parameters used to generate the bode plot shown in figure 7. table 3. bode plot parameters parameter value units comment r l 10.4 application speci? c c out 15 f application speci? c r esr 10 m application speci? c r o 0.4 m not adjustable c c 60 pf not adjustable c pl 3.3 pf adjustable r c 100 k not adjustable r1 402 k adjustable r2 133 k adjustable v out 5 v application speci? c v in 3.3 v application speci? c g ma 35 mho not adjustable g mp 7.5 mho not adjustable l 2.7 h application speci? c f s 1.3* mhz not adjustable *2.1mhz for lt3467a from figure 7, the phase is C138 when the gain reaches 0db giving a phase margin of 42. this is more than adequate. the crossover frequency is 37khz. frequency (hz) gain (db) phase (deg) 50 40 30 20 10 0 C10 C20 C30 C40 C50 0 C45 C90 C135 C180 C225 C270 C315 C360 C405 C450 100 10k 100k 1m 3467 f07 1k gain phase figure 7. bode plot of 3.3v to 5v application typical applications lithium-ion to 6v step-up dc/dc converter gnd v in sw shdn fb v in 2.7v to 4.2v d1 l1 2.2h r1 501k lt3467 3467 ta02 c2 15f c3 1.8pf c1 2.2f r2 133k v out 6v 275ma at v in = 2.7v 490ma at v in = 3.8v 590ma at v in = 4.2v c1, c2: x5r or x7r, 6.3v d1: on semiconductor mbrm120 l1: sumida cr43-2r2 shdn ss c4 0.047f i out (ma) efficiency (%) 200 95 90 85 80 75 70 65 60 55 50 3467 ta02b 100 50 300 400 500 600 700 v in = 3.8v v in = 4.2v v in = 2.7v li-ion to 6v
lt3467/lt3467a 12 3467afe typical applications 4-cell to 5v sepic converter gnd v in sw shdn fb 4v to 6.5v d1 l1 10h l2 10h 255k lt3467 3467 ta03 c1 2.2f c4 0.047f 4-cell battery c2 10f c3 1f 84.5k v out 5v 325ma at v in = 4v 400ma at v in = 5v 450ma at v in = 6.5v c1, c3: x5r or x7r, 10v c2: x5r or x7r, 6.3v shdn ss c5 4.7pf d1: philips pmeg 2010 l1, l2: murata lqh32cn100k33l 5v to 40v boost converter gnd v in sw shdn fb v in 5v d1 l1 2.7h r1 412k lt3467 3467 ta04a c2 1f c1 4.7f c3 0.1f r2 13.3k v out 40v 20ma c1: x5r or x7r, 6.3v c2: x5r or x7r, 50v d1: on semiconductor, mbrm140 l1: sumida cd43-2r7 shdn ss 15v dual output converter with output disconnect gnd v in sw ss fb v in 5v d1 c4 1f d2 l1 10h r1 147k c5 1f c6 0.047f lt3467 d3 d4 3467 ta05 c2 2.2f c3 2.2f c1 2.2f r3 1 r2 13.3k C15v 100ma 15v 100ma c1: x5r or x7r, 6.3v c2 to c5: x5r or x7r, 16v d1 to d4: philips pmeg 2005 l1: sumida cr43-100 shdn off on r4 1
lt3467/lt3467a 13 3467afe typical applications 9v, 18v, C9v triple output tft-lcd bias supply with soft-start gnd v in sw fb v in 3.3v d5 l1 4.7h r1 124k lt3467 3467 ta06a c5 10f c4 1f c1 2.2f c2 0.1f c6 1f r2 20k 9v 220ma C9v 10ma 18v 10ma c1: x5r or x7r, 6.3v c2,c3, c5, c6: x5r or x7r, 10v c4: x5r or x7r, 25v d1 to d4: philips bat54s or equivalent d5: philips pmeg 2005 l1: panasonic elt5kt4r7m ss v shdn shdn 3.3v 0v c7 0.1f d1 d4 d3 d2 c3 0.1f i l1 0.5a/div 9v output 5v/div 18v output 10v/div C9v output 5v/div 2ms/div 3467 ta06b start-up waveforms 8v, 23v, C8v triple output tft-lcd bias supply with soft-start i l1 0.5a/div 8v output 5v/div 23v output 10v/div C8v output 5v/div 2ms/div 3467 ta07b start-up waveforms gnd v in sw ss fb v in 3.3v d7 l1 4.7h r1 113k lt3467 3467 ta07a c7 10f c6 1f c1 2.2f c2 0.1f c8 1f r2 21k 8v 270ma C8v 10ma 23v 10ma c1: x5r or x7r, 6.3v c2 to c4, c7, c8: x5r or x7r, 10v c5: x5r or x7r, 16v c6: x5r or x7r, 25v d1 to d6: philips bat54s or equivalent d7: philips pmeg 2005 l1: panasonic elt5kt4r7m 3.3v 0v c9 0.1f d1 d5 d6 d2 c3 0.1f c4 0.1f c5 0.1f d3 d4 shdn v shdn
lt3467/lt3467a 14 3467afe typical applications gnd v in sw shdn fb v in 2.6v to 4.2v d1 l1 0.9h r1 8.06k lt3467a 3467 ta09a c2* 22f c4* 75pf c1 4.7f r2 2.67k v out 5v 600ma at v in = 4.2v 360ma at v in = 3.3v 250ma at v in = 2.6v c1, c2: x5r or x7r, 6.3v d1: philips pmeg 2010 l1: fdk mipw3226d0r9m *c2 can be 10f in a 1210 or larger package with the addition of c4, otherwise c4 is optional ss c3 0.047f off on i out (ma) efficiency (%) 95 90 85 80 75 70 65 60 55 50 400 3467 ta09b 100 50 150 250 350 450 200 300 500 v in = 3.3v v in = 4.2v v in = 2.6v single li-ion cell to 5v boost converter ef? ciency 2.6v-3.3v to 5v boost converter ef? ciency gnd v in sw shdn fb v in 2.6v to 3.3v d1 l1 1.5h r1 8.06k lt3467a 3467 ta08a c2 10f c4 56pf c1 4.7f r2 2.67k v out 5v 430ma at v in = 3.3v 270ma at v in = 2.6v c1, c2: x5r or x7r, 6.3v d1: philips pmeg 2010 l1: fdk mip3226d1r5m ss c3 0.047f off on i out (ma) efficiency (%) 90 85 80 75 70 65 60 55 50 400 3467 ta08b 100 50 150 250 350 450 200 300 500 v in = 3.3v v in = 2.6v 3.3v to 15v, 135ma step-up converter ef? ciency gnd v in sw shdn fb v in 3.3v d1 l1 6.8h r1 16.5k lt3467a 3467 ta10a c2 2.2f c4 68pf c1 4.7f r2 1.5k v out 15v 135ma c1: x5r or x7r, 6.3v c2: x5r or x7r, 16v d1: philips pmeg 2010 l1: sumida cmd4d13-6r8mc ss c3 0.047f off on i out (ma) efficiency (%) 3467 ta10b 90 80 70 60 50 40 30 40 80 100 20 60 120 140 160
lt3467/lt3467a 15 3467afe package description ddb package 8-lead plastic dfn (3mm 2mm) (reference ltc dwg # 05-08-1702 rev b) 2.00 p 0.10 (2 sides) note: 1. drawing conforms to version (wecd-1) in jedec package outline m0-229 2. drawing not to scale 3. all dimensions are in millimeters 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on the top and bottom of package 0.40 p 0.10 bottom viewexposed pad 0.56 p 0.05 (2 sides) 0.75 p 0.05 r = 0.115 typ r = 0.05 typ 2.15 p 0.05 (2 sides) 3.00 p 0.10 (2 sides) 1 4 8 5 pin 1 bar top mark (see note 6) 0.200 ref 0 C 0.05 (ddb8) dfn 0905 rev b 0.25 p 0.05 2.20 p 0.05 (2 sides) recommended solder pad pitch and dimensions 0.61 p 0.05 (2 sides) 1.15 p 0.05 0.70 p 0.05 2.55 p 0.05 package outline 0.25 p 0.05 0.50 bsc pin 1 r = 0.20 or 0.25 s 45 o chamfer 0.50 bsc
lt3467/lt3467a 16 3467afe 1.50 C 1.75 (note 4) 2.80 bsc 0.30 C 0.45 6 plcs (note 3) datum a 0.09 C 0.20 (note 3) s6 tsot-23 1005 2.90 bsc (note 4) 0.95 bsc 1.90 bsc 0.80 C 0.90 1.00 max 0.01 C 0.10 0.20 bsc 0.30 C 0.50 ref pin one id note: 1. dimensions are in millimeters 2. drawing not to scale 3. dimensions are inclusive of plating 4. dimensions are exclusive of mold flash and metal burr 5. mold flash shall not exceed 0.254mm 6. jedec package reference is mo-193 3.85 max 0.62 max 0.95 ref recommended solder pad layout per ipc calculator 1.4 min 2.62 ref 1.22 ref s6 package 6-lead plastic tsot-23 (reference ltc dwg # 05-08-1636) package description
lt3467/lt3467a 17 3467afe information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. revision history rev date description page number e 04/10 updated note 2 in absolute maximum ratings and electrical characteristics 2, 3 (revision history begins at rev e)
lt3467/lt3467a 18 3467afe linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2003 lt 0410 rev e ? printed in usa related parts typical applications part number description comments lt1615/lt1615-1 300ma/80ma (i sw ), high ef? ciency step-up dc/dc converter v in : 1v to 15v, v out(max) = 34v, i q = 20a, i sd < 1a, thinsot package lt1618 1.5a (i sw ), 1.25mhz, high ef? ciency step-up dc/dc converter 90% ef? ciency, v in : 1.6v to 18v, v out(max) = 35v, i q = 1.8ma, i sd < 1a, ms package ltc1700 no r sense ?, 530khz, synchronous step-up dc/dc controller 95% ef? ciency, v in : 0.9v to 5v, i q = 200a, i sd < 10a, ms package ltc1871 wide input range, 1mhz, no r sense current mode boost, flyback and sepic controller 92% ef? ciency, v in : 2.5v to 36v, i q = 250a, i sd < 10a, ms package lt1930/lt1930a 1a (i sw ), 1.2mhz/2.2mhz, high ef? ciency step-up dc/dc converter high ef? ciency, v in : 2.6v to 16v, v out(max) = 34v, i q = 4.2ma/5.5ma, i sd < 1a, thinsot package lt1946/lt1946a 1.5a (i sw ), 1.2mhz/2.7mhz, high ef? ciency step-up dc/dc converter with soft-start high ef? ciency, v in : 2.45v to 16v, v out(max) = 34v, i q = 3.2ma, i sd < 1a, ms8 package lt1961 1.5a (i sw ), 1.25mhz, high ef? ciency step-up dc/dc converter 90% ef? ciency, v in : 3v to 25v, v out(max) = 35v, i q = 0.9ma, i sd < 6a, ms8e package ltc3400/ ltc3400b 600ma (i sw ), 1.2mhz, synchronous step-up dc/dc converter 92% ef? ciency, v in : 0.85v to 5v, v out(max) = 5v, i q = 19a/300a, i sd < 1a, thinsot package ltc3401 1a (i sw ), 3mhz, synchronous step-up dc/dc converter 97% ef? ciency, v in : 0.5v to 5v, v out(max) = 5.5v, i q = 38a, i sd < 1a, ms package ltc3402 2a (i sw ), 3mhz, synchronous step-up dc/dc converter 97% ef? ciency, v in : 0.5v to 5v, v out(max) = 5.5v, i q = 38a, i sd < 1a, ms package lt3464 85ma (i sw ), high ef? ciency step-up dc/dc converter with integrated schottky and pnp disconnect v in : 2.3v to 10v, v out(max) = 34v, i q = 25a, i sd < 1a, thinsot package no r sense is a trademark of linear technology corporation. gnd v in sw ss fb v in 5v d1 l1 4.7h r1 115k lt3467 3467 f08a c2 10f c4* 22pf c1 2.2f c3 0.047f r2 13.3k v out 12v 270ma c1: x5r or x7r, 6.3v c2: x5r or x7r, 16v d1: philips pmeg 2010 l1: sumida cr43-4r7 *optional shdn shdn i out (ma) 50 efficiency (%) 100 250 200 150 300 350 3467 f08b 90 85 80 75 70 65 60 55 50 ef? ciency figure 8. 5v to 12v, 270ma step-up converter ef? ciency i out (ma) efficiency (%) 200 95 90 85 80 75 70 65 60 55 50 3467 f09b 100 50 150 250 300 gnd v in sw shdn fb v in 5v d1 l1 3.3h r1 115k lt3467a 3467 f09a c2 10f c4 12pf c1 4.7f r2 13.3k v out 12v 260ma c1: x5r or x7r, 6.3v c2: x5r or x7r, 16v d1: philips pmeg 2010 l1: sumida cdrh4d18-3r3 ss c3 0.047f off on figure 9. 5v to 12v, 260ma step-up converter

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